The invention relates to a tufting knife for a tufting machine for the production of cut pile.
Tufting machines for the production of cut pile have basically been known and have been in use for a long time. For example, document DE 27 45 793 C discloses a tufting machine, said machine comprising always the same basic components including a reed with reed fingers for supporting the planar backing material, a bar with tufting needles for rhythmically piercing the backing material and for thus pulling the thread loops into the backing material, a gripper bar with grippers for picking up the produced loops, and a knife bar with knives for cutting open said loops. In the course of the loop-forming process the knife bar and the gripper bar are moved relative toward each other in such a manner that, respectively, one knife abuts against the lateral surface of each gripper, pushes against said lateral surface, and then uses its cutting edge to cut through one or several of the loops picked up by the gripper. This process proceeds reliably only if the knives are pressed against the flanks of the griper so that the resultant cutting gap between the cutting edge of the gripper and the cutting edge of the knife is close to zero.
The knife contact pressure existing between the knife and the gripper causes the grippers and also the knives to be worn, thus limiting the useful life of the knife and/or the gripper. This is true, in particular, when the gripper comprises a hard metal insert that has an increased abrasive effect on the knife.
For example, tufting grippers and tufting knives comprising a hard metal cutting body affixed by soldering are known from DE 1 535 764.
Furthermore, DE 28 56 344 discloses the mounting of tufting knives in a knife block on a bar. As is obvious, the knife block is adapted to the thickness of the knives. If knives displaying greater flexibility and consequently lower thickness are to be used, the knife block must be changed. This represents a considerable expense.